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Ann Harrington, a member of the Yarmouth County Ground Search and Rescue team that assists the Yarmouth Shark Scramble annually, holds a baby mako that was found inside a blue shark during the 2013 event.
Ann Harrington, a member of the Yarmouth County Ground Search and Rescue team that assists the Yarmouth Shark Scramble annually, holds a baby mako that was found inside a blue shark during the 2013 event. - Carla Allen

Marine scientists use tournaments to answer multiple questions about sharks

YARMOUTH - The Aug. 15-18 Yarmouth Shark Scramble has made several changes to its rules and regulations this year.

Blue sharks are the only species eligible for the tournament. Porbeagle, mako and thresher sharks are not permitted as they have been in the past.

Warren Joyce, aquatic fisheries technician at the Bedford Institute of Oceanography in the Maritimes Region, Canadian Shark Research lab, has attended many past shark tournaments in Yarmouth.

He says the decision to allow only blue sharks is a result of a ruling by the International Commission for the Conservation of Atlantic Tunas (ICCAT), which governs all large pelagics in the North Atlantic.

“They had a meeting in the spring and recent data coming out of the States suggested that those sharks in particular are in serious decline,” he says.

Joyce added that the threshers have been on the International Union for Conservation of Nature and Natural Resources as being threatened for years.

“Since we’ve only caught six in the 25 years of all the derbies, we just decided it’s better to leave them in the water rather than take them out,” he says. “It’s interesting for us, but we don’t get enough animals to make it important for science to collect any data.”

Yarmouth Shark Scramble organizer Bob Gavel says the event is focusing on a high concentration of tag and release this year. For naysayers who say a large percentage of those fish die, Joyce says that’s not true.

“We certainly do get back a fair number of returns, probably more than what we would expect from the amount of animals we take,” he says.

“The tags that we’re using don’t cause a lot of damage. They’ve been known to work well in the past,” he adds. “We don’t think there’s any reason why these animals would die from the tagging experience.”

Joyce says from a scientific perspective, the tournaments are used to try and answer questions about the diet, age and growth of the blue shark, the impacts of the landings of the tournaments in regard to the overall population, as well as exploitation rates – how often the sharks are caught and recaptured in the fishing gear.

Although Department of Fisheries and Ocean scientists will not be dissecting sharks during this year’s shark tournament, other organizations are sending teams to collect samples.

“We’ve pretty much gone as far as we can go with dissections on the wharf,” Joyce says about their research.

Nesime Askin has been the biologist in residence for the Oceanographic Environmental Research Society (OERS) since 2014.

Her research work focuses on the impact of pollutants, such as heavy metals on various types of marine species. These can occur naturally in the environment, but there are also anthropomorphic sources that are of high concern because these contaminants are detrimental to human and animal health in the long run.

“The key heavy metals that our research work focuses on are mercury, lead, arsenic, and cadmium to name a few,” she says. “To date, we have a long-term research program studying the amount of contaminants in whales and seals, and in recent years we are focusing on sharks as they are important sentinel species in the marine environment.”

During the shark scramble they will be working alongside DFO scientists to study each shark that is landed. Once body measurements are measured, she and other OERS scientists and students will collect the various organs in individual sharks for analyses.

“Because sharks are an apex predator, knowing the amount of heavy metals in them will give us an indication of the ‘health’ status of their species, which we can then extrapolate to the marine environment,” she says.

This year OERS is providing a shark research experience opportunity to three university students. The students will work alongside Askin and Dr. Carin Wittnich, the lead OERS scientist and professor from the University of Toronto.

The students will be spending the week learning about the biology of different shark species through dissection, assisting at the shark scramble to collect research samples for the heavy metal work and learn about the ecology and conservation issues of sharks.

“We hope that this research experience will stimulate young academics to pursue careers in the marine sciences and advance our knowledge about sharks and what needs to be done to protect their environment,” says Askin.

More about the Yarmouth Shark Scramble: an interview with the Yarmouth Shark Scramble organizer - Bob Gavel

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